RF phased-array beamforming systems with long range and high throughput are desired for many applications such as communications backhauling and high-speed routing in Wireless Gigabit (WiGig) or other consumer wireless systems. Many applications favor low-power solutions operating in the millimeter-wave range—in particular the 57 to 86 GigaHertz (GHz) range—that are scalable Multiple Input Multiple Output (MIMO) systems with flexible transmit and receive partitioning for different customers. Other desirable features include ease of production testing, high inter-channel isolation, and robust thermal and mechanical behavior.
Nevertheless, designing such RF beamforming systems presents a number of challenges. If digital beamforming is to be used, the baseband processing to support the large channel bandwidth (e.g., 250 MHz to 2 GHz) would require prohibitively high power consumption by high-speed Analog-to-Digital Converters (ADCs) and Digital-to-Analog Converters (DACs). If analog beamforming is to be used, the long ranges (e.g., above 200 meters for backhauling) and large modulation constellations (above QAM16) would present severe requirements for Signal-to-Noise Ratio (SNR) and jitter. These noise and jitter requirements would be heightened by the non-linearities introduced by phase-shifting at high power and high frequency and would further constrain the design's flexibility and scalability.